Put oatmeal in bowl and sprinkle with salt. Cover with warm water about 1/2 inch above oatmeal. (Decrease water if you like oatmeal a little thicker.) Microwave for 1 min. on high, remove bowl and stir. Microwave 30 seconds, stir again. Continue to microwave in 15 second intervals, stirring after each 15 seconds, until oatmeal reaches desired consistancy. (My microwave is very powerful, so I didn't make it past the minute and a half.) Be careful that it doesn't boil over when you get to the end of cooking. (Mine did) Remove oatmeal and stir in peanut butter and sprinkle with ground cinnamon if desired. Serve hot.